本程序为PWM程序,使用时注意使用时钟程序shizhong()，在SMCLK为1MHZ时，最大频率为10KHZ,SMCLK为8MHZ时，最大频率约为80KHZ,

可通过直接调用函数得到PWM波，如果需要两个占空比的PWM,按下列函数说明修改，否则可删除屏蔽部分-The procedure for the PWM program, note the use of using a clock program shizhong (), in SMCLK is 1MHZ, the maximum frequency of 10KHZ, SMCLK is 8MHZ, the maximum frequency of about 80KHZ, PWM wave can be obtained by calling the function, if you need two duty cycle of the PWM, the following function descr iptions modify, or delete the shield section